07 PT Cruiser Start Issues

Long shot here, but true story, worth mentioning. Yours could be a starter, but like Demonracer menrioned,
load test the battery!
As a young mechanic, I once had a bad plate in a battery. When the internal plate moved, the battery died. No start, customer called AAA, put the car up on a tow hook. When we received the car at the shop, it started right up.
Crazy. Intermittent short drove me nuts.
Only found it after the 2nd time it happened.